Proximity sensing device

ABSTRACT

A proximity sensing device employing a fluid sensing jet which follows a helical path and which generates an above-ambient pressure signal when interrupted.

United States Patent [1 1 Beeken 51 Jan. 9, 1973 [54] PROXIMITY SENSINGDEVICE [75] Inventor: Basil B. Beeken, New Haven, Conn.

[73] Assignee: Automatic Switch Co., Florham Park, NJ.

[22] Filed: Jan. 22, 1971 [2]] Appl. No.: 108,875

[52] US. Cl. ..73/37.5 [51] lnt. Cl. ..G01b 13/12 [58] Field of Search..73/37.5

[56] References Cited UNITED STATES PATENTS 3,481,180 12/1969 Jones..73/37.5

3,545,256 12/1970 Beeken ..73/37.5 3,127,764 4/1964 Hudson ,.73/37.53,243,992 1/1966 Woods ..73/37.5 3,673,856 3/1970 Panigati ..73/37.5

Primary Examiner-Louis R. Prince Assistant ExaminerFrederick ShoonAttorney-Alan 1-1. Levine [57] ABSTRACT A proximity sensing deviceemploying a fluid sensing.

jet which follows a helical path and which generates an above-ambientpressure signal when interrupted.

l3 Claims, Drawing Figures PROXIMITY SENSING DEVICE BACKGROUND OF THEINVENTION In conventional pneumatic proximity sensing devices theeffective sensing range is usually limited to a small fraction of aninch. This characteristic restricts use of such sensors to thoseapplications where the possible positional deviation of an object to besensed from a normal position is very limited. Where an object must besensed over a wider area other more complex sensing means must be used.

SUMMARY OF THE INVENTION The instant invention utlizes a particular kindof nozzle apparatus for generating a helical fluid stream and fordirecting such stream along a predetermined axis. This helical stream orjet when projected freely along said axis is capable of retaining itsgeometric shape over a longer distance than a conventional sensing fluidstream which moves longitudinally along said axis and thus will be ableto sense the presence of objects over a greater range from said nozzleapparatus.

The primary object of the instant invention is to provide an improvedfluid operated proximity sensor having a greater effective sensingrange.

Another object of the invention is to provide a pneumatic proximitysensor which utlizes a helical sensing jet.

Other objects of the invention will become apparent as the disclosureprogresses.

In the drawings:

FIG. 1 is an axial sectional view of a preferred embodiment of theinstant invention.

FIG. 2 is a cross sectional view taken along section line 2-2 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings theinstant apparatus comprises an inner member .or barrel having a reducedcylindrical tip 11, an intermediate cylinder section 12, an enlargedshoulder 13 and a cylindrical end connector portion 14. An outer tubularhousing or member 15 is coaxially threadedly mounted as at 16 on saidbarrel so as to surround the said intermediate section 16 of said innermember thereby establishing an annular shaped flow chamber 17. The lefthand end of housing 15, as seen in FIG. 1, is formed with a radiallyinwardly extending end wall 18 that has a radially disposed inner wallsurface 20, the latter being axially spaced from the adjacent andsubstantially radially disposed portion of the end wall surface 21defining the right hand end of intermediate section 12. Surfaces 20 and21 cooperatively define an annular orifice 22. The wall surface 21arcuately tapers, as illustrated in the drawings, inwardly and axiallyso as to merge with the substantially cylindrical outer surface 23 ofthe said axially extending tip 11. An axial bore is formed through thebarrel 10, said bore having a reduced tip portion 24, a slightlyenlarged intermediate portion 25, and a further enlarged connectorportion 26.

The cylindrical wall of the outer member 15 is formed with an aperture27 in which a suitable fitting (not shown) is secured so as to allowfluid such as air to be directed tangentially into the said annularchamber 17. Further, the cylindrical wall of the intermediate barrelsection 12 is formed with a relatively small radially extending bleedhole 30 which when certain pressure conditions exists, will permit acertain amount of fluid to flow from the annular chamber 17 to the saidaxial bore 25 in the barrel 10.

In operation supply fluid under pressure is introduced into chamber 17through aperture 27 and flows in a helical path towards and through theannular orifice 22. After leaving orifice 22 the helical flow continuesalong the arcuately tapered outer surface 23 of the tip 11 and inleaving said tip will establish a miniature tornado like jet or helicalflow pattern indicated at 31, the latter extending for a considerableoperative range or distance d from the end of said barrel tip 11. Areduced static fluid pressure is established at the core, i.e., at thecenter of this free flowing helical fluid path the core also extendingover the said operative distance d. This free helical flow and thereduced static pressure at the center thereof diminish to ineffectiveintensity at points beyond said distance a'. The reduced static pressureat the center of flow 31 causes a corresponding reduced or below-ambientpressure to exist in the bore of the barrel 1%) which in turn causesfluid to bleed from chamber 17 through bleed hole 30 and towards tip 11as indicated by arrow 33. Under these normal flow conditions the fluidoutput pressure P existing at the output end of the connector boreportion 26 of barrel 10 is substantially at ambient pressure. When anobject 35 to be sensed penetrates or disrupts the helical flow 31 apressure rise will occur at'the center of said flow pattern 31 whereuponmore of the fluid flow through bleed hole 30 is diverted towards theopposite end of the barrel bore as indicated by arrow 36. This will giverise to an increase in-said output pressure P to a level above theambient level, which pressure increase will be sustained as long as theobject 35 remains in a flow disrupting position as illustrated inFIG. 1. Removal of the object from intercepting relation with respect tothe helical flow pattern 31 will cause the output pressure P to drop toits said normal level.

As will be apparent the above described rise in the output pressure P,constitutes a reliable indication of the presence of the object 35within the proximity range (1 of the sensing stream and this effectiverange, when using a helical flow sensing jet 31, is substantiallygreater than where a conventional axial flow type of sensingjet isemployed. Thus it may be seen that the instant proximity sensing device,in having a greater sensitivity range, is suitable for use in manyapplications where conventional fluid proximity sensors would beinoperative.

Since the foregoing description and drawings are merely illustrative,the scope of protection of the invention has been more broadly stated inthe following claims; and these should be liberally interpreted so as toobtain the benefit of all equivalents to which the invention is fairlyentitled.

I claim:

1. A fluid operated proximity sensing device: comprising a tubularbarrel having a fluid guiding outer surface at one end thereof; and

means cooperating with said barrel for establishing a helical fluid flowpattern about said surface, which helical flow continues along thebarrel axis beyond said end of said barrel; said means including ahousing defining a chamber around said barrel;

the outer-end of said barrel having a tapered tip, the outer surface ofa portion of said tip defining together with said housing an exhaustorifice from said chamber;

saidhelical flow establishing a reduced pressure at the center of saidflow pattern and in the inside of saidtubular barrel, whereby when anobject to be sensed interrupts said helical flow a pressure rise will becreated at the center of said flow pattern and on the inside of saidbarreLsaid pressure rise constituting a signal indicating the presenceof the object being sensed.

2. Apparatus as defined by claim 1 wherein a fluid flow conduit isprovided between said chamber and the inside of said barrel.

3. A fluidoperated proximity sensing device: comprising an inner memberhaving a fluid conducting passagewayforrned therethrough;

an outer member mounted on said inner member and formed so astocooperatively form with said inner member a flow chamber;

said. members also defining an annular orifice through which air mayexhaust in following a helical path;

the portion of said inner member helping to define said orifice beingtapered; and

said outer member being formed so as to permit pressure fluid to followa helical path towards and through said orifice whereby when an objectto be sensed intercepts said helically moving fluid flow downstream ofsaid orifice a pressure rise is generated in said passageway. 1

4. Apparatus as defined by claim 3 wherein said chamber is annular inshape, and said outer member is formed so as topermit fluid underpressure to be admitted tangentially into said chamber.

5. Apparatus as defined by claim 4 wherein said inner member is providedwith a passage that interconnects said chamber and said first mentionedpassageway.

6. A fluid operated proximity sensing device; comprising a housing meansdefining a flow chamber into which fluid is introduced so as to flowhelically about an axis;

means directing said helical flow along an axis beyond the effective endof said housing means; said directing means including walls defining anannular orifice, the inner of said walls being tapered; and meansdefining a pressure output conduit which communicates with the centerofsaid helical flow beyond the effective end of said housing means.

1. A fluid operated proximity sensing device: comprising a tubularbarrel having a fluid guiding outer surface at one end thereof; andmeans cooperating with said barrel for establishing a helical fluid flowpattern about said surface, which helical flow continues along thebarrel axis beyond said end of said barrel; said means including ahousing defining a chamber around said barrel; the outer end of saidbarrel having a tapered tip, the outer surface of a portion of said tipdefining together with said housing an exhaust orifice from saidchamber; said helical flow establishing a reduced pressure at the centerof said flow pattern and in the inside of said tubular barrel, wherebywhen an object to be sensed interrupts said helical flow a pressure risewill be created at the center of said flow pattern and on the inside ofsaid barrel, said pressure rise constituting a signal indicating thepresence of the object being sensed.
 2. Apparatus as defined by claim 1wherein a fluid flow conduit is provided between said chamber and theinside of said barrel.
 3. A fluid operated proximity sensing device:comprising an inner member having a fluid conducting passageway formeDtherethrough; an outer member mounted on said inner member and formed soas to cooperatively form with said inner member a flow chamber; saidmembers also defining an annular orifice through which air may exhaustin following a helical path; the portion of said inner member helping todefine said orifice being tapered; and said outer member being formed soas to permit pressure fluid to follow a helical path towards and throughsaid orifice whereby when an object to be sensed intercepts saidhelically moving fluid flow downstream of said orifice a pressure riseis generated in said passageway.
 4. Apparatus as defined by claim 3wherein said chamber is annular in shape, and said outer member isformed so as to permit fluid under pressure to be admitted tangentiallyinto said chamber.
 5. Apparatus as defined by claim 4 wherein said innermember is provided with a passage that interconnects said chamber andsaid first mentioned passageway.
 6. A fluid operated proximity sensingdevice; comprising a housing means defining a flow chamber into whichfluid is introduced so as to flow helically about an axis; meansdirecting said helical flow along an axis beyond the effective end ofsaid housing means; said directing means including walls defining anannular orifice, the inner of said walls being tapered; and meansdefining a pressure output conduit which communicates with the center ofsaid helical flow beyond the effective end of said housing means.